The present invention relates to spectral photometers, of the type comprising a light source, means for receiving light transmitted from the light source and reflected from the object of interest and including a monochromator, as well as means for measuring the received light.
In medicine, diagnostic significance has always been attached to the appearance of the skin, especially the relationship between the coloration of the skin and the flow of blood through skin tissue. However, the color of the skin, in so far as its dependence upon the flow of blood through skin tissue is concerned, depends upon a combination of factors, such as perfusion, the amount and composition of the blood in the capillaries of skin tissue, and the color of the blood hemoglobin, i.e., the degree of oxygenation of the hemoglobin. Accordingly, the actual significance of the coloration of the skin, i.e., for diagnostic purposes, can be quite ambiguous.
In view of this, it would be desirable to be able to separate, at least to some degree, the effects upon the overall appearance of the skin respectively attributable to the various parameters in question. Of course, not only the appearance and coloration of skin, but of other organ surfaces as well, is of interest. With such an object in mind, one possibility would be to evaluate the coloration of the skin with the help of a spectrometer. However, such devices are not only quite expensive but also unwieldy.
Of the factors influencing the appearance and coloration of skin, the single most important one is the conversion of hemoglobin from oxygenated to desoxygenated state (explained for example in Lubbers, Niesel, Pflugers Achiv, "Kurzzeit Spektral Analysator," volume 268, page 286 (1956).